Why a third edition? Wainright's first edition was well received and Apache was improved after the edition was published. So he produced a second edition. Guess what? The open source Apache has continued to accrue infalling upgrades. As Wainright explains, there are now two main versions, 1.3 and 2. Apache 1.3 is essentially the direct descendent of earlier versions. Very stable on unix/linux, on which it was originally developed.

But the key thing about this new book is its descriptions of Apache 2. Apache 1.3 had inferior performance on Microsoft computers, when it was ported. Some people got fed up with this state of affairs and recast crucial portions, to produce Apache 2, which now directly uses native MS threads. It has much better performance than 1.3, on MS computers.

The book goes into this in fuller detail. Plus it has the usual voluminous descriptions of what you can tweak for most web server needs. Luckily, if you want to deploy or use a vanilla configuration, the early chapters should suffice. Then consult the later text for more specialised needs.

If you are already running Apache 1.3 on a unix/linux computer, it seems from this book that there is little incentive to migrate to 2. Relatively little to gain.